As has been said, there are a number of filters that convert from native
word processor input, or output, to HTML. This means that we do not
have to force a "house style" on course authors at the point they
write the material. We get the house style that the reader's WWW
client program is configured for. It also obviates the learning of a
new package by authors!

One interesting problem though with letting people author their
material in many different systems is that of maintaining links. Each
word processing package has its own idea of references or citations or
bibliographies. Indeed, some systems even have hypertext built in
nowadays, but of their own design. We would like to make sure that
URLs can be associated with similar kinds of logical links in original
source documents - e.g. references/citations in papers, course notes
(to papers, books (ISBNs), other courses etc). Depending on the
filter, it may be possible to translate these into URLs appropriately.

On the other hand, it may be necessary to persuade people to start to
use different ways of specifying links in the package they are using,
so that the filter for that package can translate these
correctly into URLs. This latter approach is used, for example in
the excellent LaTeX2html tool from Nikos Drakos at Leeds University in the UK.

Filters that are in common use include:

latex2html - deals with LaTeX to HTML. You can annotate your LaTeX
source so that references, in LaTeX form, become links in HTML - this
is ideal for developing course material that is structured.

fm2html or WebMaker - deal with Frame conversion to HTML.

groff2html - converts groff to HTML.

ms2html - converts nroff with ms macros to HTML

mm2html - as ms2html, but with MM macros - we had to roll our own just
to see how easy it was.

rtf2html/rtftohtml - convert RTF (Rich Text Format) which is the most
common intermediate form for PC Word Processing packages. This is,
unfortuantely, operating at a level below where one can extract true
document structure, so is not generally as succesful as tools that
convert from document source forms.

There are also many useful ancillary tools (pstogif) for converting
pictures from one bitmap format to another.